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J/A+A/509/A3        Earth Orientation Catalog 4 (EOC-4)         (Vondrak+, 2010)

The Earth Orientation Catalog 4. An optical reference frame for monitoring Earth orientation in 20th century. Vondrak J., Stefka V. <Astron. Astrophys. 509, A3 (2010)> =2010A&A...509A...3V
ADC_Keywords: Fundamental catalog ; Positional data Keywords: astrometry - reference systems - catalogs Abstract: The astrometric ground-based observations of latitude / universal time variations, covering the interval 1899.7-2003.0, were used in combination with Hipparcos / Tycho positions and some older ground-based catalogs to construct a family of catalogs, tailored for long-term Earth rotation studies. These catalogs, called Earth Orientation Catalogs (EOC-1 through EOC-3) yielded more accurate proper motions than the original Hipparcos Catalogue, and its latest version, EOC-3, even periodic motions for a large portion of the stars. About 4.5 million observations made at 33 observatories are combined with the catalogs ARIHIP, TYCHO-2 etc... in order to obtain EOC-4. Spectral analysis of ground-based data and comparison with the USNO Sixth Catalog of Orbits of Visual Binary Stars are used to discover which of the observed objects display periodic motions, and improved combination procedures are used. The catalog contains 4418 different objects (i.e., stars, components of double stars, photocenters), out of which 599 have significant orbital motions. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file eoc4.dat 287 4418 IV version of Earth Orientation Catalogue
See also: I/239 : The Hipparcos and Tycho Catalogues (ESA 1997) I/259 : The Tycho-2 Catalogue (Hog+ 2000) J/A+A/463/783 : Combined astrometric catalogue EOC-3 (Vondrak+, 2007) Byte-by-byte Description of file: eoc4.dat
Bytes Format Units Label Explanations
1- 6 I6 --- Seq Star number 8- 18 F11.5 s RAsec [0/86400] Right ascension (ICRS, Ep=J2000) 20- 31 F12.4 arcsec DEsec [-324000/324000] Declination (ICRS, Ep=J2000) 33- 40 F8.5 arcsec/yr pmRA Proper motion in right ascension multiplied by cos(declination) (pmRA*cos(DE)) 42- 49 F8.5 arcsec/yr pmDE Proper motion in declination 51- 55 F5.2 yr EpRA Epoch of RA (offset 1900) 56- 61 F6.2 mas e_RAsec rms uncertainty in RA at EpRA multiplied by cos(declination) 63- 67 F5.2 mas/yr e_pmRA rms uncertainty in pmRA 69- 73 F5.2 yr EpDE Epoch of DE (offset 1900) 74- 79 F6.2 mas e_DEsec rms uncertainty in DEsec at EpDE 81- 85 F5.2 mas/yr e_pmDE rms uncertainty in pmDE 87- 93 F7.4 arcsec plx Trigonometric parallax 95-100 F6.1 km/s RV Radial velocity 102-106 F5.2 mag mag Apparent magnitude 108-113 F6.2 yr P1 Period P1 (1/f1) (1) 114-119 F6.2 yr P2 Period P2 (1/f2) (1) 122-128 F7.4 arcsec c1R c1R coefficient (1) 131-137 F7.4 arcsec s1R s1R coefficient (1) 140-146 F7.4 arcsec c2R c2R coefficient (1) 149-155 F7.4 arcsec s2R s2R coefficient (1) 158-164 F7.4 arcsec c3R c3R coefficient (1) 167-173 F7.4 arcsec s3R s3R coefficient (1) 176-182 F7.4 arcsec c4R c4R coefficient (1) 185-191 F7.4 arcsec s4R s4R coefficient (1) 194-200 F7.4 arcsec c1D c1D coefficient (1) 203-209 F7.4 arcsec s1D s1D coefficient (1) 212-218 F7.4 arcsec c2D c2D coefficient (1) 221-227 F7.4 arcsec s2D s2D coefficient (1) 230-236 F7.4 arcsec c3D c3D coefficient (1) 239-245 F7.4 arcsec s3D s3D coefficient (1) 248-254 F7.4 arcsec c4D c4D coefficient (1) 257-263 F7.4 arcsec s4D s4D coefficient (1) 265-270 F6.2 mas e_ARA rms uncertainty in amplitudes of RA 272-277 F6.2 mas e_ADE rms uncertainty in amplitudes of DE 279 I1 --- AE [0/3] Astrometric excellency (2) 281-283 A3 --- CAT Astrometric Catalogue (3) 285 A1 --- BS [ABPQ] Binary system (4) 287 I1 --- PF [1/3]? How the periods were found out (5)
Note (1): Equations: RA(t) = RA+[pmRA*t+c1R*cos(arg1)+s1R*sin(arg1)+c2R*cos(2*arg1) +s2R*sin(2*arg1)+c3R*cos(arg2)+s3R*sin(arg2) +c4R*cos(2*arg2)+s4R*sin(2*arg2)]/15cos(DE) DE(t) = DE+pmDE*t+c1D*cos(arg1)+s1D*sin(arg1)+c2D*cos(2*arg1)+s2D*sin(2*arg1) +c3D*cos(arg2)+s3D*sin(arg2)+c4D*cos(2*arg2)+s4D*sin(2*arg2) where arg1 = 2*π*t/P1, arg2 = 2*π*t/P2, t = time in years from J2000.0 Note (2): Astrometric excellency from 3 (highest rank) to 0 (lowest rank) Note (3): Catalogue that was combined with Earth Orientation observations as follows: F61 = Sixth Catalogue of Fundamental Stars I. F63 = Sixth Catalogue of Fundamental Stars III. GCH = Combination of Hipparcos with Boss' General Catalogue HIP = Hipparcos Catalogue PPM = Position and Proper Motion catalogue TYC = Tycho Catalogue T2H = Tycho-2 XXX = 'local' catalogue Note (4): Binary system as follows: A = component A B = component B P = photocenter Q = other (404214 is the photocenter of stars 104214 and 104217) Note (5): How the periods were found out as follows: 1 = Period was found by spectral analysis only. 2 = Period was found both by spectral analysis and in the USNO Sixth Catalog of Orbits of Visual Binary Stars, their difference was smaller than a 20% relative tolerance, catalog's period was accepted. 3 = The difference between the two values for the period exceeded the tolerance, period found by spectral analysis was not statistically significant, but for the period taken over from the Sixth Catalog the condition of significance was met.
Acknowledgements: Jan Vondrak, vondrak(at)ig.cas.cz, Vojtech Stefka, stefka(at)ig.cas.cz
(End) Jan Vondrak [AI ASCR, Czech Rep.], Patricia Vannier [CDS] 13-Oct-2009
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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